Assessing Migratory Performance in Collision-Surviving Birds With Motus¶

Motus Logo
Bird Collision
Bird with Telemetry Tag

This notebook analyzes migratory bird data from the Motus Wildlife Tracking System, specifically focusing on the Motus Northeast Collision Project. The project tracked six species that survived window collisions in the Lake Erie region (Cleveland and Pittsburgh) during 2018:

  • American Woodcock
  • White-throated Sparrow
  • Gray Catbird
  • Ovenbird
  • Wood Thrush
  • Magnolia Warbler

Background¶

Window collisions pose a severe threat to migratory bird populations, estimated to kill up to one billion birds annually. This research examines birds that survived collisions and were rehabilitated before being released with Motus nanotags for tracking. To learn more about the bird windows collision phenomenon, check out this article.

Research Focus¶

The analysis assesses migratory performance of collision-surviving birds by examining:

  • Detection probabilities
  • Migration patterns
  • Travel speeds and distances
  • Comparative analysis between rehabilitated and wild birds

Data Source¶

Data comes from the Motus Wildlife Tracking System (specifically the Northeast Collision Project), which uses automated radio-telemetry technology to track tagged birds with high geospatial accuracy.

The complete research paper can be found here.

Analysis Questions¶

Population Demographics¶

  • What is the distribution of rehab vs non-rehab birds?
    • Total counts by status
    • Breakdown by species
    • Detection frequencies
    • Repeat detections analysis (birds detected multiple times)

Spatial Analysis¶

  • What are the movement patterns?
    • Geographic distribution of detections
    • Range/territory size analysis
    • Movement corridors identification

Initial import of Python libraries

Helper Functions¶

Main Analysis¶

Successfully loaded with mac_roman encoding
Detections dataframe loaded with 17989 rows and 17 columns
CPU times: user 88.1 ms, sys: 98.9 ms, total: 187 ms
Wall time: 5.4 s

With the dataframe loaded, we can begin our analysis.

1. Population Demographics¶

  • What is the distribution of rehab vs non-rehab birds?
    • Total counts by status
    • Breakdown by species
    • Detection frequencies
    • Repeat detections analysis (birds detected multiple times)
Found 36 unique tags

Found 6 unique species:

	1. White-throated Sparrow
	2. American Woodcock
	3. Gray Catbird
	4. Ovenbird
	5. Wood Thrush
	6. Magnolia Warbler
Detections per species:

speciesEN.x
Wood Thrush               9374
Gray Catbird              6394
American Woodcock         1415
Magnolia Warbler           719
Ovenbird                    53
White-throated Sparrow      13
Name: count, dtype: int64


Top 5 receivers by detection count:
recvDeployName
PARC Banding       9877
PARC Honey Hut     7967
Churchill - Fen      15
Long_Point_Tip       12
43.6:-79.35          11
Name: count, dtype: int64

Bottom 5 receivers by detection count:
recvDeployName
Napanee LOSH       1
PARC Mt. Laurel    1
Curries            1
Merlin             1
39.8:-79.7         1
Name: count, dtype: int64
Summary Statistics:
-----------------
AMWO: 5 total birds (4 rehab [80.0%], 1 wild)
WTSP: 5 total birds (1 rehab [20.0%], 4 wild)
GRCA: 9 total birds (6 rehab [66.7%], 3 wild)
OVEN: 7 total birds (4 rehab [57.1%], 3 wild)
WOTH: 6 total birds (3 rehab [50.0%], 3 wild)
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<Figure size 1500x600 with 0 Axes>
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Detection Patterns Key Observations:¶

  1. Species Detection Peaks: The highest peak is seen for the Ovenbird (Rehab) in early June, reaching nearly 1,000 detections. The Ovenbird (Wild) also shows a high detection rate around the same time but at a lower intensity.
  2. Species with Lower Detections: Other species like the American Woodcock, White-throated Sparrow, Gray Catbird, Magnolia Warbler, and Wood Thrush have relatively lower and more sporadic detection patterns throughout the year. Their peaks are considerably lower than the Ovenbird detections.
  3. Seasonal Patterns: There appears to be a seasonal trend where bird detections, especially for Ovenbird species, spike in early summer and decrease significantly afterward, with some smaller fluctuations seen in the fall.

Spatial Analysis¶

Using the MovingPandas library, we can analyze the movement patterns of the birds by creating trajectory data structures.

Built on top of GeoPandas and Pandas, this library provides a robust framework for trajectory analysis using the time-series data we already have from Motus.

According to its documentation, MovingPandas follows the trajectories = timeseries with geometries approach of modeling movement data.

Ultimately the trajectory represents a series of connected points in space and time. Adding them to the dataframe as a GeoDataFrame with a geometry column makes them easier to work with compared to the base data alone.

Trajectory Type: <class 'movingpandas.trajectory_collection.TrajectoryCollection'>
tag_id species rehab_status duration_hours length_km avg_speed_kmh
0 24345 Ovenbird Y 86.592500 1946.312371 22.476685
1 24376 Gray Catbird N 0.284722 10.167210 35.709227
2 28413 Magnolia Warbler N 97.042778 524.176398 5.401498
3 28414 White-throated Sparrow N 2.795000 246.577979 88.221101
4 28415 Magnolia Warbler Y 344.381389 0.000000 0.000000
5 28416 White-throated Sparrow N 0.001389 0.000000 0.000000
6 28419 Magnolia Warbler Y 0.216944 0.000000 0.000000
7 28420 American Woodcock Y 141.028889 0.000000 0.000000
8 28422 Gray Catbird Y 20.001389 0.000000 0.000000
9 28423 White-throated Sparrow Y 3.750833 178.202314 47.510059
10 28425 Ovenbird Y 6.085556 212.006862 34.837717
11 28426 White-throated Sparrow N 1.318056 63.250001 47.987356
12 28428 American Woodcock Y 170.930278 0.000000 0.000000
13 28429 Gray Catbird Y 17.289167 0.000000 0.000000
14 28433 Magnolia Warbler Y 20.295000 233.226498 11.491821
15 28434 Wood Thrush N 3037.487778 0.000000 0.000000
16 28436 Gray Catbird Y 678.899444 536.068231 0.789614
17 28440 Wood Thrush N 1.468889 0.000000 0.000000
18 28441 Gray Catbird Y 1085.320833 1080.091990 0.995182
19 28445 American Woodcock N 3686.137778 54.662266 0.014829
20 28446 Gray Catbird Y 35.117500 0.000000 0.000000
21 28448 Wood Thrush Y 194.942500 0.000000 0.000000
22 28449 American Woodcock Y 274.779167 0.000000 0.000000
23 28451 American Woodcock Y 4058.609444 615.327421 0.151610
24 28452 Ovenbird N 407.132778 1050.644321 2.580594
25 28453 Gray Catbird Y 226.470278 0.000000 0.000000
26 28455 Wood Thrush Y 78.456944 318.946884 4.065247
27 28457 Wood Thrush Y 3344.478333 603.590712 0.180474
28 28458 Gray Catbird N 0.912778 45.675547 50.040161
29 28460 Gray Catbird N 74.215833 63.250001 0.852244
30 28761 Ovenbird N 0.068056 0.000000 0.000000
31 28763 Wood Thrush N 2877.911389 0.000000 0.000000
Overall Summary by Rehab Status:
             duration_hours                                 length_km          \
                      count    mean      std   min      max     count    mean   
rehab_status                                                                    
N                        13  783.60  1393.28  0.00  3686.14        13  158.34   
Y                        19  567.77  1143.10  0.22  4058.61        19  301.25   

                                   avg_speed_kmh                            
                 std  min      max         count   mean    std  min    max  
rehab_status                                                                
N             306.41  0.0  1050.64            13  17.75  28.58  0.0  88.22  
Y             499.64  0.0  1946.31            19   6.45  13.61  0.0  47.51  
Trajectory Counts by Species:
                        Wild  Rehab  Total
species                                   
American Woodcock          1      4      5
Gray Catbird               3      6      9
Magnolia Warbler           1      3      4
Ovenbird                   2      2      4
White-throated Sparrow     3      1      4
Wood Thrush                3      3      6
Detailed Species Summary:
                                    duration_hours                             \
                                             count     mean      std      min   
species                rehab_status                                             
American Woodcock      N                         1  3686.14      NaN  3686.14   
                       Y                         4  1161.34  1932.37   141.03   
Gray Catbird           N                         3    25.14    42.50     0.28   
                       Y                         6   343.85   443.32    17.29   
Magnolia Warbler       N                         1    97.04      NaN    97.04   
                       Y                         3   121.63   193.17     0.22   
Ovenbird               N                         2   203.60   287.84     0.07   
                       Y                         2    46.34    56.93     6.09   
White-throated Sparrow N                         3     1.37     1.40     0.00   
                       Y                         1     3.75      NaN     3.75   
Wood Thrush            N                         3  1972.29  1708.64     1.47   
                       Y                         3  1205.96  1852.93    78.46   

                                             length_km                    \
                                         max     count     mean      std   
species                rehab_status                                        
American Woodcock      N             3686.14         1    54.66      NaN   
                       Y             4058.61         4   153.83   307.66   
Gray Catbird           N               74.22         3    39.70    27.04   
                       Y             1085.32         6   269.36   451.36   
Magnolia Warbler       N               97.04         1   524.18      NaN   
                       Y              344.38         3    77.74   134.65   
Ovenbird               N              407.13         2   525.32   742.92   
                       Y               86.59         2  1079.16  1226.34   
White-throated Sparrow N                2.80         3   103.28   128.07   
                       Y                3.75         1   178.20      NaN   
Wood Thrush            N             3037.49         3     0.00     0.00   
                       Y             3344.48         3   307.51   301.96   

                                                     avg_speed_kmh         \
                                        min      max         count   mean   
species                rehab_status                                         
American Woodcock      N              54.66    54.66             1   0.01   
                       Y               0.00   615.33             4   0.04   
Gray Catbird           N              10.17    63.25             3  28.87   
                       Y               0.00  1080.09             6   0.30   
Magnolia Warbler       N             524.18   524.18             1   5.40   
                       Y               0.00   233.23             3   3.83   
Ovenbird               N               0.00  1050.64             2   1.29   
                       Y             212.01  1946.31             2  28.66   
White-throated Sparrow N               0.00   246.58             3  45.40   
                       Y             178.20   178.20             1  47.51   
Wood Thrush            N               0.00     0.00             3   0.00   
                       Y               0.00   603.59             3   1.42   

                                                          
                                       std    min    max  
species                rehab_status                       
American Woodcock      N               NaN   0.01   0.01  
                       Y              0.08   0.00   0.15  
Gray Catbird           N             25.30   0.85  50.04  
                       Y              0.47   0.00   1.00  
Magnolia Warbler       N               NaN   5.40   5.40  
                       Y              6.63   0.00  11.49  
Ovenbird               N              1.82   0.00   2.58  
                       Y              8.74  22.48  34.84  
White-throated Sparrow N             44.17   0.00  88.22  
                       Y               NaN  47.51  47.51  
Wood Thrush            N              0.00   0.00   0.00  
                       Y              2.30   0.00   4.07  

Geographic distribution of detections¶

The Motus detection dataset originates from the Motus Northeast Collaboration network. Plotting the receiver locations and the detected bird movements on a map can help us visualize the coverage and detectability of the network.

The northeast region of the US is covered by 37 receivers (as of Q4 2019), as shown in the maps below.

Number of receivers: 37

Receivers are color-coded by the number of detections they have recorded in total.

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Plotting Trajectories¶

Simple trajectories can be plotted with Matplotlib using with each bird's tag ID, using the MovingPandas TrajectoryCollection object. From the base dataset this dataset is just a series of points with a location and timestamp, so this plot gives a quick representation of the detected bird movements as lines as well. MovingPandas has a number of additional functionalities for smoothing or otherwise interpolating the trajectories (my custom function is not one of them).

No description has been provided for this image

Plotting the detected bird movements on a map can help us visualize the coverage and detectability of the network.

From the Folium map below, we can see that the birds were detected in a number of locations across the northeast region of the US and southern Ontario on both sides of Lake Erie and Lake Ontario.

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White-throated Sparrow
White-throated Sparrow

Image sources: Wikimedia Commons, Animalia.bio

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American Woodcock
American Woodcock

Image sources: Wikimedia Commons, Animalia.bio

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Gray Catbird
Gray Catbird

Image sources: Wikimedia Commons, Animalia.bio

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Ovenbird
Ovenbird

Image sources: Wikimedia Commons, Animalia.bio

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Wood Thrush
Wood Thrush

Image sources: Wikimedia Commons, Animalia.bio

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Magnolia Warbler
Magnolia Warbler

Image sources: Wikimedia Commons, Animalia.bio

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Challenges¶

While conducting this analysis, several challenges were encountered that may impact the interpretation of results:

  1. Limited Sample Size

    • The dataset included a relatively small number of birds, which poses significant limitations for drawing broad conclusions.
    • Species Diversity: The limited number of species represented in the sample may not accurately reflect the overall diversity of the bird population in the study area. This could lead to an underestimation of the ecological richness and the potential impacts of environmental changes on various species.
    • Unique Birds Detected: The small sample size also means that the number of unique individuals detected was low. This raises concerns about the representativeness of the data and may highlight striking declines in bird populations that are already occurring.
      • For instance, if only a few individuals of a species are detected, it may indicate that the population is at risk or declining, which could be a critical signal for conservation efforts.
  2. Implications for Conservation

    • The findings from this limited dataset should be interpreted with caution. While they may suggest trends or patterns, they may not provide a complete picture of the bird populations in the area.
    • Future studies should aim to increase sample sizes and include a broader range of species to better understand population dynamics and inform effective conservation strategies.

Addressing these challenges is crucial for ensuring that the insights gained from this analysis contribute meaningfully to our understanding of avian ecology and the urgent need for conservation efforts in the face of declining bird populations.

Future Research Opportunities¶

While this current workbook focuses on Population Demographics and Spatial Analysis, there are several other valuable analyses that could be conducted with this ecological data. Below are some suggested topics for future exploration:

  • Detection Network Analysis

  • Receiver Effectiveness: Assess the performance of the receiver network in detecting birds.

    • Coverage Analysis: Map the geographical distribution of receivers and identify gaps in coverage.
    • Detection Frequency: Analyze the number of detections per receiver to determine which receivers are most effective.
    • Temporal Patterns: Investigate how detection rates vary over time, identifying peak detection periods and potential seasonal trends.
  • Comparative Analysis

  • Behavioral Comparisons: Examine differences in movement and behavior between rehab and wild birds.

    • Movement Patterns: Compare trajectory characteristics, such as speed and distance traveled, to understand how rehabilitation affects bird behavior.
    • Survival and Detection Rates: Analyze the survival rates of rehab birds versus wild birds, including how often they are detected over time.
    • Territory Size: Calculate and compare home ranges of rehab and wild birds to assess habitat use and territorial behavior.
    • Seasonal Behavior Patterns: Explore how movement and detection patterns change with the seasons, providing insights into migratory behavior and habitat preferences.

These analyses can provide deeper insights into the ecological dynamics of bird populations, the effectiveness of rehabilitation efforts, and the role of environmental factors in shaping bird behavior. Future work could expand on these themes to enhance our understanding of avian ecology and inform conservation strategies.

Questions?¶

Feel free to reach out to me by email with any questions or comments!

Keon Monroe